Core Needle Biopsy Versus Fine-Needle Aspiration for Lymph Node Evaluation in Breast Cancer: Diagnostic Accuracy and Cost Analysis in a Public Health System

OBJECTIVES: Accurate lymph node evaluation is essential for breast cancer staging, treatment planning, and the diagnosis of recurrent disease. Fine-needle aspiration (FNA) and core needle biopsy (CNB) are the 2 main percutaneous techniques used, but they differ in diagnostic yield, complication rates, and associated healthcare costs. To compare the diagnostic performance and economic impact of FNA vs CNB for lymph node evaluation in breast cancer patients within the Brazilian public healthcare system, emphasizing the relevance of cost-effective strategies in low- and middle-income countries. METHODS: A retrospective cohort study was conducted, including women with clinically suspicious lymph nodes who underwent FNA or CNB between 2015 and 2023. Diagnostic outcomes and rates of inconclusive results were compared. An economic analysis based on a decision-tree model assessed the cost-effectiveness of each strategy from the public payer's perspective. RESULTS: Among 300 biopsies analyzed, CNB demonstrated significantly lower rates of inconclusive results compared with FNA (2.7% vs 50.7%, P < .05). Although the initial cost of FNA was lower, the need for additional procedures after inconclusive results made CNB more cost-effective overall. A CNB-led diagnostic strategy reduced total costs by nearly 50% compared with an FNA-led pathway. CONCLUSIONS: CNB offers superior diagnostic performance and greater economic efficiency compared with FNA for lymph node evaluation in breast cancer. Prioritizing CNB as the first-line diagnostic approach could improve resource allocation in public healthcare systems, particularly in low- and middle-income countries where cost-effectiveness is crucial to expanding access to high-quality cancer care.